Multi-objective Reactive Power Management using Differential Evolution

Reactive Power Management (RPM) is one of the most significant tasks for proper operation and control of a power system. Reactive Power Management reduces power system losses by adjusting the reactive power control variables such as generator voltages, transformer tap-settings and other sources of reactive power such as capacitor banks or FACTS devices. RPM provides better system voltage control resulting in improved voltage profile, system security, power transfer capability and overall system operation. RPM is a complex combinatorial optimization problem involving nonlinear functions having multiple local minima and nonlinear and discontinuous constraints. In this paper, the RPM problem is formulated as nonlinear constrained multi-objective optimization problem with equality and inequality constraints for minimization of power losses and voltage deviation simultaneously. This multi-objective problem is solved using Differential Evolution (DE), which is a population based search algorithm. Weighing factor method has been employed for finding Pareto optimal set for RPM problem. Fuzzy membership function is used to find the best compromise solution out of the available Pareto-optimal solutions. The proposed approach has been demonstrated on the standard IEEE-30 bus system.